Accuracy of Mammograms Varies by Radiologist

“When a woman gets a mammogram, she wants to know that if she has breast cancer, the mammogram will be likely to detect it,” said study leader Diana Miglioretti, PhD, an associate investigator at Group Health Center for Health Studies. “This is especially important when the woman has a breast concern such as a lump.”

Therefore, the research team examined how well 123 radiologists interpreted nearly 36,000 diagnostic mammograms done to evaluate breast problems, such as lumps, from 1996 through 2003 at 72 U.S. facilities, including six from Group Health, that contribute data to the Breast Cancer Surveillance Consortium.

For different radiologists, sensitivity ranged from 27 percent to 100 percent; and false-positives, from 0 to 16 percent. These differences were only partially explained by the characteristics of the patients and the experience of the radiologists.

The radiologists who read diagnostic mammograms most accurately tended to be those who were based at academic medical centers or spent at least 20 percent of their time on breast imaging. By contrast, unlike in Europe, most U.S. women get mammograms interpreted by general radiologists who interpret mammograms as only a small percentage of their practice.

“We need to reduce the wide variability among radiologists in how they interpret diagnostic — and screening — mammograms,” said Miglioretti. “A good way to do that may be to identify the radiologists who are least accurate at reading mammograms — and to improve their performance with extra training.” The national Breast Cancer Surveillance Consortium is working on ways to accomplish these goals, including developing an interactive training program.